Electronic systems for monitoring television viewing are known. As the number of sources of television programming for the home viewer has increased, and as home viewing systems have increased in complexity, greater capabilities have been demanded of monitoring systems.
It has become common for home viewing systems to include a video cassette recorder (VCR) or a cable converter module, or both of those items of equipment, in addition to the television receiver. In a viewing system including both a VCR and a cable converter, a variety of modes of operating the system are possible. For example, a program may be viewed on the TV "off-air", i.e., from a signal received via an RF antenna, at the same time that another program, received via the cable converter, is recorded on magnetic tape by the VCR. Alternatively, a program received via the cable converter may be viewed while a program is recorded off-air by the VCR. Another possibility is that a program may be recorded off-air while a different program is viewed off-air. In still another possible mode of operation, program material previously recorded by the VCR, off-air or from cable, may be played back by the VCR and viewed on the TV. Of course, it is also possible to play back and view a prerecorded tape, such as a rented or purchased film or exercise video.
The addition of a second VCR to the viewing system can add still further possibilities, including recording of a program off-air or from cable by a first VCR at the same time that a rented or purchased videotape, or previously recorded program, is played back by the second VCR and viewed on the TV.
There is accordingly a need for a system that is capable of monitoring all of the modes of television viewing that are possible in viewing systems which include cable access and/or one or more VCRs. Such a monitoring system should also be readily adaptable to home viewing systems that do not include some or all of these elements. Moreover, since many of the people whose television viewing is to be monitored are volunteers, it is desirable that the television monitoring system be easy to use and that the system can be installed with a minimum of disruption to the viewer's equipment. It is also important that the monitoring system not impede television viewing. Further, it is a strong preference of people whose viewing is to be monitored that the monitoring system not require installation of probes or other modification of the television receiver and VCR owned by the viewer.
It is also desired that the system's needed versatility and ease of use be achieved without great expense.